The present invention relates to the formation of casement frames, and in particular to means for joining channel members into a casement frame.
A casement frame is known from German publication DE-PS No. 2,130,496, in which an assembly of two channel-shaped section members are connected by means of a continuous plastic strip. The plastic strip is designed as a solid rod, hence is expensive as to its material. The solid rod is applied with laterally flexing arms, which snap behind the projection formed on the section channels when they are fitted together. Thus, the construction requires great dimensional precision. Great difficulty is encountered in maintaining the toluenes, particularly with respect to the plastic section. Rubbery, elastic spring bodies, effective only in the direction normal to the plane of the window or panel contained in the casement, have been used to clamp the plastic strip to the interior of the channel section, and thus, the tolerance problem is partially solved. The problem is not entirely solved with respect to the design of the laterally flexing arms of the plastic strip.
Another design is shown in German publications DOS No. 1,914,843, and DAS No. 1,955,591, wherein the plastic strip is formed as an H-shaped section. The freely extending lateral webs thereof are resiliently compressable and engage into corresponding grooves or depressions formed in the channel section members.
Such connection, however, is not strong enough, especially in the direction parallel to the plane of the window or panel, and additional measures for locking the sectional parts together are required.
It is an object of the present invention to provide a casement frame assembly, which avoids the foregoing objections, and which is simple and inexpensive to form.
It is a further object of the present invention to provide a casement frame assembly, wherein a plastic spacer strip is anchored in such a way to the section channel members, that a secure locking of the spacer strip is insured, without any overy high requirement for accuracy of size and dimensional configuration. It is still another object of the present invention to provide a casement frame assembly, which has improved sound absorption as well as increased heat-insulation.